This pretty much is a custom transformation where what if Insted of gohan getting the mystic form vegeta and goku learn it. Goku would be high buuhan level because mystic gohan was Super Buu level SSJ3 Goku is equal to buuhan so mystic goku would be stronger or a bit weaker then buuhan. Mystic vegeta would be Super Buu (gotenks) level and stronger than Kid Buu. In total these transformations would be cool to see and would have gave more light on vegeta . It would have been cool to see vegeta goku and gohan train at the same time for the mystic form but goku already had ssj3 in the buu arc so there was no need for goku to train for a mystic form and vegeta could have gotten stronger from a mystic form but he already had ssj2 in the buu arc.